Rackett parameter

Tj. is the reduced temperature, T is the critical temperature, is the critical pressure, and is the modified Rackett parameter as given in the supplemental table for pure-component properties. 

VSTR = O Connell characteristic volume parameter, cm /g-mol ZRA = Rackett equation parameter RD = mean radius of gyration, A DM = dipole moment, D R = UNIQUAC r Q = UNIQUAC q QP = UNIQUAC q ... 

Ra parameter of Rackett s method, determined for each component, i... 

Rackett s parameter for the mixture = molecular weight for the mixture [kg/kmol]... 

An afternate method with approximately the same accuracy as the Rackett method is the COSTALD metnod of Hanldnson and Thomson.The critical temperature, a characteristic volume near the critical volume, and an acentric factor optimized for vapor pressure prediction by the Soave equation of state are required input parameters. The method is detailed in the Technical Data Book ... 

The determination of molar volumes of molecular species in the liquid phase can be performed with the Rackett equation [58], requiring critical temperature, pressure and volume as well as a further fitting parameter. It is possible to calculate the molar volumes of electrolyte species using the two-parameter equation of Clarke (see Ref. [52]). 

A modification of the Rackett method by Spencer and Danner [Spencer, C. F., and R. R Danner,/. Chem. Eng. Data, 17 (1972) 236] replaces Z with an adjustable parameter Zra... 

The table below lists the density of several common solvents in the temperature range from 0°C to 100°C. The values have been calculated from the Rackett Equation using parameters in the reference. Density values refer to the liquid at its saturation vapor pressure thus entries for temperatures above the normal boiling point are for pressures greater than atmospheric. 

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